Please either change the visibility of the fields in the title to protected or implement getters returning references to the according object variables. This would allow further inheritance and an efficient way to display SD card details and use the same object to also read/write to SD.

With the current implementation, one has to set up an Sd2Card object just to obtain the type (and other card information) and then an additional SD object, which has an Sd2Card field. This does not make much sense.